Orthoester stabilized polyvinyl-chloride resins



United States Patent 3,515,694 ORTHOESTER STABILIZED POLYVINYL- CHLORIDE RESINS Louis L. Wood, Washington, D.C., assignor to W. R. Grace & Co., New York, N.Y., a corporation of Connecticut No Drawing. Original application Dec. 12, 1966, Ser. No. 612,066. Divided and this application May 22, 1968, Ser. No. 750,690

Int. Cl. C08f 45/58 US. Cl. 26045.8 3 Claims ABSTRACT OF THE DISCLOSURE Polyvinyl chloride resins are stabilized by the addition of orthoester compounds having a structure BCOR7CR wherein R is selected from the group consisting of hydrogen, alkyl, phenyl, phenylalkyl, alkylphenylalkyl, halophenyl, nitrophenyl, and alkenyl; and R is alkylene. A polyhydric alcohol may also be added in a concentration of from 1% to 10% to further enhance thermal stability.

The present application is a division of my application 612,066 filed Dec. 12, 1966, now abandoned, which in turn is a continuation-in-part of my earlier filed applications, Ser. No. 403,353, filed Oct. 12, 1964 now abandoned and 499,093, filed Oct. 20, 1965 now abandoned.

The present invention relates to the stabilization of resins, and more specifically to a novel stabilization agent for stabilizing vinyl chloride polymers and copolymers against the degradation effects of elevated temperatures.

It is well known that vinyl chloride containing resins degrade at elevated temperatures. When vinyl chloride polymers and copolymers are subjected to molding temperatures in excess of about 150 C. they tend to discolor. Serious discoloration occurs even in the relatively short period of time required for a molding operation.

To date, numerous stabilizers have been suggested for use in vinyl chloride type resins. The most satisfactory of these stabilizers comprise tin, lead and cadmium containing compounds. These compounds, while performing satisfactorily where toxicity is not a problem, cannot be used where the treated polymer is to come into contact with foodstuffs and the like.

As of present, a highly effective polyvinyl chloride stabilizer which does not possess toxic characteristics or propensities has not been developed.

It is therefore an object of the present invention to provide a novel class of polyvinyl chloride stabilizers.

It is another object to provide novel stabilizers for polyvinyl chloride containing resins which substantially enhance thermal stability of said resins.

It is a further object to provide a class of polyvinyl chloride stabilizers which are non-toxic and may be used in resins which are used in the packaging of foodstuff materials.

These and still further objects of the present invention will become readily apparent to one skilled in the art from the following detailed description and specific examples.

Patented June 2, 1970 Broadly, my present invention contemplates as polyvinyl chloride stabilizers compounds containing the following ortho ester grouping:

wherein the indicated unsatisfied valences are occupied by hydrogen or organic radicals. It is also contemplated that these orthoesters may be effectively combined with polyhydric alcohols to give a superior degree of stabilizatlon.

More specifically, I have found that if from about 1% to about 10% by weight of a compound containing an ortho ester grouping is admixed with polyvinyl chloride, the ortho ester compound will stabilize the polyvinyl chloride towards heat induced degradation. Furthermore, this stabilization effect may be enhanced by the addition of polyhydric alcohols.

The ortho esters used in the practice of the present invention may be broadly defined as those ortho esters which possess at least one of the above defined ortho ester groups, and which are compatible with the polyvinyl chloride resins at the processing temperatures indicated. By the term compatible it is meant that the ortho ester used should homogenously blend with the polyvinyl chloride and should have a relatively low vapor pressure at processing temperatures so as not to cause excessive foaming of the resins at the processing temperatures encountered.

Typical structures of suitable ortho esters which may be used in the practice of my invention are:

wherein R may represent hydrogen, alkyl, phenyl, phenylr alkyl, alkylphenylalkyl, halophenyl, nitrophenyl and alkenyl; R R R may be alkyl, phenyl, phenyl-alkyl, alkylphenyl, and alkyl-phenylalkyl wherein R, R and R have the meaning given above (1); R may be alkylene, phenylene, alkylalkylene, alkenylene,

alkenyl-alkoxy-alkylalkylene and alkynylene; and n has a value of from 1 to 4.

Ri le) wherein R has the meaning given above and R is alkylene.

The reaction products of lower orthoesters such as triethyl orthoacetate and triethylorthoformate with polyols such as glycerol, sorbitol, and mannitol yield complex esterified products.

Specific examples of orthoesters which may be used in the present invention along with a general description of how the orthoester compound may be prepared are given in the following paragraphs. (The numeral designations will be used in the subsequent specific examples and claims to identify these compounds.)

The following three methods may be used to prepare the following orthoesters:

(A) Iminoester route, as set forth in Pinner, Ber., 16 356, 1644 (1883).

The appropriate nitriles are reacted with one equivalent of dry hydrogen chloride and one equivalent of alcohol to form an iminoester hydrochloride which is then alcoholyzed with an excess of alcohol to form the orthoester. The reaction may be outlined as follows:

A dinitrile can be used as follows:

Furthermore, diols may be used at either one or both steps of the synthesis.

NHzCl NHzCl ZRON Hon H 21101 RCOROCR 2HOROH (B) Exchange reaction as described by Mkhitaryan, V. J. Gen. Chem. (USSR) 8 1361 (1938).

The alkoxy groups of a readily available orthoester such as triethyl orthoacetate or formate are displaced by a higher boiling alcohol or polyol as follows:

Furthermore, the reaction may be carried out in two steps with two different alcohols or polyols including polyols ranging from diols to hexols. Typically the reaction may be illustrated for a diol as follows:

When more complex polyols including triols through hexols are used, many complex polymeric products are possible. However, these reaction products are formed by continuing the reaction until the required amounts of lower alcohol has been removed. That is the exchange reaction is continued until .the calculated amount of lower alcohol is displaced by the higher alcohols.

(C) Alcoholysis of trihalomethyl groups as set forth by Sah, P. and Ma, S. T., J. Am. Che. Soc. 54 2964 (1932).

The appropriately substituted trichloromethyl compound is treated with a metal alkoxide.

(I) O CzHs CH 0 02115 CH CO-CHCHr-O(E-OH 0C2H5 02115 This compound is conveniently prepared by route A or B.

(II) o 02H. 0 02H;

CH JO CH:4 OA7-CH;

This compound is prepared by route A or B.

(III) C2115 02m 5 6 CHFJJOCH2CECGHTO-(JCH3 6 J) )2115 (B5115 This compound is prepared by route A or B.

(IV) CH CH1- CHy-Cfl \CH2 OHg-C om OH; CH COCHCH2CHz-O CCH This compound is prepared by route A or B.

(v OH -CHz (HIP-CH1 t) CH C -OCH2GH OCHzOHzC C0H This compound is prepared by route A or B.

(VI) OH -CHOH-a CH2-CE-CH 0 0 CH3 CHz COJJHzCHzO CCH This compound is prepared by route A or B.

(VII) O-CH2 CHFO0CH2C CH2 CH3 OCH2 This compound is prepared by route A.

(VIII) CHzO CH2CH2CH=CH2 CH3-COCHzCH-CHzO-COH3 o o o Hfll CH2 Hz c 43H:

\O/ H C2CCHzOCH2CH=CHz C2/H5\CH2OCH2OH=CH2 This compound is prepared by route B.

(IX) (CH CH CH O) C(CH C(OCH CH CH This compound is prepared by route A or B.

(x) I o CH OYCH2C-CH2 This compound is prepared by route B. (XI) 053 /CH; 033 /CH 0 o\ Cz (3E2 (3H2 This compound is prepared by routes A and B.

This compound is prepared by route A. (XIII) (CH O CCH CH SCH CH C OCH 3 This compound is prepared by route A.

(XIV) This compound is prepared by route A. (XV) (CH O CCH CI-I OCH CH C OCH 3 This compound is prepared by route A. 3.( 2)1o CH )8 This compound is prepared by route A.

0 C(OCHm This compound is prepared by route C.

(XVII) (XVIII) CH C (0 01 1401396011 This compound is prepared by route A.

This compound is prepared by route A.

( 2 5 )3 2)4 2 5) 3 This compound is prepared by route A. (XXI) 00m 02m 005115 CH 1OCH2 0 CH3 C2H5 0 CzHs CH2OC20H=CH2 This compound is prepared by route B.

(XXII) CH2CII2 CHz-CH2 A (L I. Y GHs COCHzCHzO OOHa This compound is prepared by route B.

(XXIII) CzH5 HJJO (32115 O C2H5 This compound may be prepared by route A, B, orC.

This compound may be prepared by route B.

This compound was prepared by route B.

(XXVI) OH3C(OCH2@) 3 (XXVII) Poly(glyceryl orthoformate) This compound was prepared by way of route B using one mole of triethyl orthoacetate and one mole of glycerol.

(XXVIII) Poly(sorbityl orthoacetate) This compound was prepared by route B from 2 moles of triethyl orthoacetate and one mole of sorbitol.

(XXIX) Poly (mannityl orthoacetate) wherein R is an organic radical and x has a value of from 1 to 6. Preferably these alcohols have a boiling point in excess of about 175 C.

In the above formula R may be alkyl, alkylphenyl, phenylalkyl, alkylene, phenylene, polyalkoxyalkylene and trivalent counterparts thereof. Typical polyhydric alcohols useful in the practice of the present invention are 0, m, p-xylene, a,a-diol, trimethylolpropane monopropyl ether, trimethylolpropane monoallyl ether, propylene glycol, diethylene glycol, dimethyloctadiynediol, pentaerythritol, trimethylolpropane, neopentylglycol, benzylalcohol, cetyl alcohol and dipentaerythritol.

Polyvinyl chlorides which are treated in accordance with the practice of my present invention are those vinyl chloride polymers and vinyl chloride copolymers having a number average molecular Weight from about 10,000 to about 150,000 and a weight average molecular weight of from about 20,000 to 1,000,000. These vinyl chloride polymers and copolymers are Well known to those skilled in the art and comprise vinyl chloride homopolymers as well as vinyl chloride copolymers which are prepared by copolymerizing vinyl chloride with a copolymeriza'ble monomer such as unsaturated esters which include vinyl acetate, vinyl formate, vinyl benzoate,, vinyl stearate, vinyl oleate,

as well as diethyl maleate and diethyl formate. Copolychloride copolymers may be prepared by polymerizing vinyl chloride with vinylidene chloride. The above men- 'tioned copolymers may contain from- 0 to 20, and even 40% by weight of copolymerizable monomer.

The stabilization agents, namely the ortho esters contemplated herein, are incorporated with the vinyl chloride polymer and copolymers by any conventional means. The blending may be conveniently carried out first preparing a slurry of finely divided polymer in a solvent for the ortho ester such as methanol, acetone, ethyl ether. The solution is then separated from the slurry and the polymer particles are dried. This results in polymer particles which are thoroughly coated with the ortho esters set forth herein. It is also contemplated that the blending may be achieved by milling the polymer at the softening temperatures therefor until an intimate blend of the stabilizaerally conducted at conventional temperatures of to 200 C. for a period of time suflicient to obtain thorough blending of the stabilization agent with the polymer.

The stabilized vinyl chloride polymers and copolymers contemplated herein may be used in the formation of rigid polyvinyl chloride molded articles. These rigid molded pieces are formed in extrusion and injection molding devices which are well known to those skilled in the art and which operate in the neighborhood of 150 to 200 C. The stabilization agents contemplated herein effectively stabilize the vinyl chloride polymer and copolymer during the molding process and make it possible to produce rigid moldings having a low degree of color change and good clarity.

It is also contemplated that the polyvinyl chloride resins stabilized by the present stabilizers may be admixed with various plasticizers such as high boiling esters including the alkyl phthalates, phosphates, adipates, sebacates, azolates, and various polymeric type ester plasticizers. Also the present composition may contain other additives such as Zn, Mg, Sn and Ca salts of carboxylic acids, and phosphate esters. Furthermore, the resins may be included in plastisol type preparations which are fabricated by dipping and deposit type molding techniques.

Having described the basic aspects of my present invention the following specific examples are given to illustrat'e embodiments thereof.

EXAMPLE I In the examples tabulated below 9.5 g. portions of powdered Vygen 120, a high molecular weight polyvinyl chloride resin, was slurried in solutions which comprised 20 ml. of methanol and 0.5 g. of the various stabilizer compounds listed below. The resultant slurries were evaporated to dryness with constant agitation at from 40 to 60 C. and under 60 mm. Hg pressure 3.5 g. of the polyvinyl chloride mixtures were then pressed into plaques which measured 1" x 3" and mils in thickness on a press heated to 200 C. and exerting 10,000 p.s.i. for the times listed in the table below. The color of the resultant plaques were measured by comparison with the standard Gardner color scale (0.0:colorless to 5.0=dark amber). The less color developed in the plaque the more effective is the stabilizer.

Gardner Color Index at Various Times (minutes) Stabilizer 2 5 10 15 Examples 1 and 2 containing the ortho esters contemplated herein are eifectively stabilized. Example 3 which contained the well known stabilizer dibutyltin dilaurate rapidly discolored under the same conditions as did Example 4 which contained no stabilizer.

EXAMPLE II In the following runs particulate polyvinyl chloride.-

having a number average molecular weight of about 38,000 was dry blended with various amounts of orthoester and/ or polyhydric alcohol. These samples were then placed in the mixing chamber of a Brabender Plastograph r at 190 C. and open to the air. A roller speed of r.p.m. was used to knead the polymer formulations. The Brabender Plastograph continuously records the torque re- TABLE II Decomposition Concentime tration Flux after Polymer, Color Gardner Scale 0 Colorless 15 Brown Stabilizer (numerals refer ortho- (parts per time, flux, Torque, temp., Run ester described previously) hundred) min. min. 4 g. degrees 2 mins. 4 mins. 10 mins. 15 mins. 20 mins.

5. 0 2 a 2. 1. 5 26. O 1. 25 193-199 0. 2 0. 2 0. 5 1. 0 l 1. 2, 1. 5 3 gAI g: 8} 2. 0 17. 0 1. 3 195-208 1. 0 1. 0 1. 0 1. 5 4 x g 'g a' g g: 1. 5 22.0 1. 1 190-198 1. 5 1. 5 1. 5 1. 5 2 l. 5

m-Xylene a, a-di0l 2. 0 3. 5 10-13. 5 1. 9-1. 5 190-210 1. 5 15 p-Xylene a, a-di01 2. 0 3. 5 3. 0-8. 0 1. 9-1. 7 190-210 1. 5 15 o-Xylene a, a-diol.- 2. 0 2. 5 3. 5 1. 9-1. 7 190-198 15 3 V 5 0 s Tr'ih'riifiifb'rb'ri 1. 5 31. 0 1. 4-1. 2 190197 1. 0 2. 0 2. 0

ril l f ether (TMPA) g 1 0 3 o 1 9-2 2 180-194 5: o 21 0 14: 5 1: 3-11 4 190-203 1. 5 g: 8} 2. 0 12. 5 1. 4 190-200 1. 0 g: 2. 5 17. o 1. 8-2. 0 190-202 1. 0 5. 0 13 pgtligelgglene 2 0} 3. 0 25.0 1. 3-1. 4 194-207 1. 5 14 ".11". 510 2.5 19 1.4 194-207 2.0 3 3} 2. 0 27 1.1 190-198 1. 5 5. 0 2 0} 2. 0 31 1. 1 190-196 1. 0 5'. 0 2. 0 11. 5 1. 1-1. 4 190-199 2. 0 g: 2. 5 15. 5 1. 1-1. 4 188-196 1. o 5. 0 2 0 7. 5 1. 4 190-198 1. 0 5. 0 9. O 8. 5 1. 4 -192 7 1. 0 5. 0 2. 0 12. O 1. 4-1. 6 190-214 1. 5 5. 0 2. 0 8. 6 1. 4 189-196 1. 0 5. 0 1. 0 8. 5 1. 2-1. 8 -197 2. 2 5. 0 1. 0 B 12-21 1. 6-1. 8 181-210 2. 2

= Brown 4 mins mins. mins. mins.

2 mins.

TABLE II Decomposition time Flux after Polymer, Color Gardner Scale 0 Colorless 15 time, flux, Torque, temp., min. min. 4 Kg. degrees 5 7 -0 0 5 0 n n u n 0 I I I 2 0 I .2 I I. I I I I. I I ...I I I I I I 5 7 I525 I 0558 I 0 5 8 I I 00 5 I I0 I 0 I l n I e u. l I l 0 0 .11 I .3221 2 0 0 I I 22 0 I I8 I 3 I I I III I I I I I I I I I I I 5 7 30258505522m 0 5 85 I 0 I I I 0 0 21LQLO 2 2 2 2L L 0 0 0 I 232 01 5 2 I I I I I I I I I I I I u 5 7 302500 832225 5 5 8 5 3 0058M0088 0 25 5 0 5 0 0 2 1LOL 2 21211 0 0 0 0 0 0 33322 36111 1 04 6 2 7 5 7 3 0 2 0 0 0 8 2 2 5 2 5 5 3 3 3 0 flw H 0 0 2 LL L QZLL 0 0 0 0 0 0 22222 2511L L 0 11 2 2 2 7 9 6 6 2826228 331 0 0 8 9 6 808 2 G 0 4. 0 m %%M%mm%% 0 m 9 m 9 999O991090000%0 0 990 001 1 0 m n m 2 2 212111122221 1 2 1 2 1 1119 .119 .21222 O 110.1223. 0 9.2 I I a a a a e I e I 1 I5 I5 I72 o e e a 10 0 2 a o a 8 620 2 8 2 0 8 1 3 00 0 9 9 7 oo oo 7 8 7 7 7 008 8 7 0 8 00 7 c0 8 8 8 89788098999 9 9 8 9 8 799m 9 9 1 1 1 1 1 1 1 1 1 1 1 11 1 1 1 1 1 1 1 1 1 1 1111121111111 1 1 1 1 1 11 1 1 8 8 8 8 8 8 0c 8 8 Q0 8 00 8 3 8 m m m m4344 4woo444445 4 4 5 3 4 194ml A: 4 4U 4H 1 L L lLLLLLLlLLLL L L Ll1LL.LLL1 L LL 4 .1 .2105. 2 n n V 2 I I II w I T 311 .1= iv08er 8 4. 7 IV 3 1 12 12423211 I I I 2 31 333 7.. L L lLLLLLLlLLLL L L I 1111L L11 LL1 1 111 121 1 1 1 1 1 I I I I 0 5 268051171563 m 0 5 0 O 59nm50505005505 0 mm05mm M 5 5 1112.1112111 7 5 2 5 2 2 8 3 8 9 1 7349949042 E 1 99 1 2 2 1 8 2 1 1 1 L 5 6 0 0 0 0 0 0 5 0 05 0 7 5 0 0 0 0 0 5 0 0000000000550 0 5 1w 00 0 0 0 0 0 L L LLLZ LLLLQZL om L L L L L22222333 2 32 24 2 322 00 00 00000000000000000000000000000000000 0000000000000000000O 5 2 52 ImmsiIaaLflIILaazaaazaa55aaoaaoazosvdsd 5 At 25 min. Black at 7.5 min.

3. The composition of claim 1 wherein said orthoester compound has the formula At 30 min.

a Black.

8 I1l-defined.

and having Concentration parts per hundred) Run m m mmmm W wwm M I I I I I I I I I I m III III I I II I o III III I III I I I I I I I I I I I I I I I I I n III III I. IIIIII I m a I I I I e I I I I I I I I I I I I II w I I I I I I I I a I I I I I I I I I I I I II I IIII IIIIIIIIImI I I m I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 0 1 1 I 0 I I I I I I I I I I I I I I I I Im I I I I I I HI mmmm I I I I I I I I I I I I I I I I I I I I I I I a 5 0 I I I I I I I I I I I I I I I I I I I I I I I I I I I In a mam I IAIIAIA A. A IA .AIA A.AIA.. A II .m .m .m I I IPHHP I I mrfm I Imw I I Im I In I I Imnm I mm wmmwmw ex mmmmmm vmmmmm mmmmmmmwmmmhmmmvvmmnx XXW. XX axaaaa I I I II IIIIIIIIIIIII I II I II I I I I I I I I I I I I I I I I I I I I I I I w m m a w m n n a n nmonwmmm mm m 7 7 2 Black after 23.5 min. 3.5 after 30 min.

After 25 min. After 25 min I claim: 1 1. A thermally stabilized polyvinyl chloride resin composition comprising polyvinyl chloride and a compound of the formula OR1 RCO-R7 CR OR wherein R is selected from the group consisting of hydrogen, alkyl, phenyl, phenylalkyl, alkylphenylalkyl,

halophenyl, nitrophenyl and alkenyl; and R is alkylene.

2. The composition of claim 1 which contains from about 1 to about 10% by weight of an alcohol having a boiling point in excess of about C.,

the formula R(OH) wherein R is an organic radical and x has a value of from 1 to 6. 

